FR2626581A1 - FIRE RETARDANT COMPOSITE PRODUCT STRUCTURE BASED ON POLYMER FOAM, METHOD OF MANUFACTURING SUCH COMPOSITE PRODUCT, AND PARTICULAR STRUCTURES OF THIS TYPE - Google Patents

Abstract

This structure comprises a polymer foam and at least 0.5% of linear and / or non-linear carbon fibers, hot-fixed in a substantially irreversible and non-flammable manner, arranged on at least one of the surfaces of the foam and / or distributed at inside this foam, linear carbon fibers having an electrical resistance less than 4 X 10 ** 3 ohms / cm, when measured on a 6 K cable of fibers having a diameter of 7 to 20 microns being excluded, and carbonaceous fibers having an oxygen limit index value greater than 40.

Description

PRODUCT STRUCTURE COMFORT FLAME RETARDANT -

  OF POLYMER FOAM, MANUFACTURING METHOD

  OF SUCH PRODUCT COMPRESSION AND STRUCTURES

PARTICULARS OF THIS TYPE.

  The present invention relates to a flame retardant composite product consisting of a polymeric foam and

  non-flammable carbon fibers and a process for producing

  duction of a flame retardant composite product. Polymer foam composite products are flame retardant on their outer surfaces or throughout the mass

of their structure.

  The physical and mechanical properties of the foams make them useful for a wide range of applications, among which mention can be made of upholstery and bedding. However, many polymeric foams, for example

  polyurethane, are flammable in nature which

  melting and the release of harmful gases and the dispersion of combustion debris. In the case of many "classic" foams, such

  characteristics cause self-combustion

  maintained or a combustion without a progressive flame even after the flames proper have been extinguished. Cellular material is considered

  (foams> made from inflammable polymers

  They are more flammable than solid polymer materials, since the insulating effect of their cellular nature causes a rapid accumulation of heat on the surface which is subjected to heating or flame, which results in a high level of heat. high pyrolysis. In solid polymeric materials, this heat buildup occurs at a lower speed due to the higher conductivity of the solid material. Although rigid foams have a thermal conductivity behavior similar to soft foams, the highly cross-linked nature of their ohmic structure renders them less flammable than polymers and also gives them a superior natural tendency to form a protective layer of charcohn at the same time. instead of forming molten polymer droplets. what happens with soft foams. Although solid and rigid cellular foam materials burn less easily than soft foam materials and are easier to extinguish, they have an increased tendency to burn without flames and to emit

  a greater amount of toxic fumes.

  Various methods are known for reducing the flammability of polymeric foams. Commonly, for this purpose, additives such as aluminum trihydride or compounds containing phosphorus are added to the foam. Moreover, in order to reduce the flame retardancy of the foam, halogenated polyalcohols are used, in particular brominated polyalcohols such as dibromonéopentylglycol. None of

  these additives were not entirely satisfactory.

  It is known that the incorporation in a foam of trimerised polyisocyanates (for example of lisocyanurates) improves the flame retardant characteristics of said foam. For example, we used diisooyanate

  trimerized toluene to prepare flexible foams.

  Although these foams have good characteristics as foams, they have mediocidal physical properties, more particularly they show poor pressure deformations and partial crushing of the cells. By

  elsewhere, trimerized toluene diisocyanate has

  dance to rush from the solution

  disocyanate in which it is dissolved}

  void storage problems and a lack

262658 1

  uniformity in the foams prepared therefrom. The polymeric foams that are suitably used in the present invention are - selected from olefinic resins,

  styrene, urethane resins, latexes, ureas, -

  isocyanurates and the like; U.S. Patent No. 4,554. 293, 4,528,300 and 4,640,933 in Park's name describe each of the mosses

  that can be used in the present invention.

  U.S. Patent No. 4,699,931 to Fuzesi et al. Discloses polyol-free isocyanurate foams which can be used in the

present invention.

  U.S. Patent Nos. 4,489,913, 4,552,903, 4,174,137, 4,581,418, and 4,568,665 disclose various types of polyurethane foams which can be

use in the invention.

  U.S. Patent Nos. 3,770,688 and 3,960,792 describe typical polystyrene foams which are

  can use in the present invention.

  U.S. Patent No. 4,669,943 in the name of Ber-

  trand describes self-polystyrene foams

  fire extinguishers with improved thermal properties. These foams are mixed with a fireproofing agent consisting of tribromopentaerythritol. Those are

  foams with self-supporting characteristics

  extinguishers can be further improved by

present invention.

  European Patent Demanae No. 0199567,

  published on October 29, 1986 and on behalf of F.P. McCul-

  lough and others, entitled "Carbon fibers with reversible elastic deformation and their method of

  "manufacture" describes non-flammable carbonaceous fibers

  which can be advantageously used to provide improvements in flame retardancy to polymeric foams in accordance with

present invention. -

  The term "stabilized" as used herein refers to fibers or wicks that have been oxidized at a specific temperature, typically less than

  about 2509C for aoryl fibers. -We understand

  that in some cases the filament and / or the fibers are oxidised with the aid of chemical oxidants

lower temperatures.

  The term "reversible deformation" as used herein applies to a compression spring which is helicoidal or sinusoidal in shape. In particular, reference is made to the "Me-hanioal Design - Theory-and Praotice" publication ( Mechanical Design - Theory and Practice ", MacMillan Publishing Co., 1975, pages 719 to 748, plus

  particularly section 14-2, pages 721 to 724.

  The term "permanently" or irreversibly hot-fixed "as used herein applies to non-linear carbon fibers which have been heat-treated until they have a degree of irreversibility according to which, once they have been stretched in a substantially rectilinear form, without exceeding their internal tensile strength, these fibers substantially return to their non-rectilinear initial shape, once the

  stress applied to these fibers.

  The term "electrical resistance" as applied to the carbonaceous fibers used in the

  present invention applies to. the electrical resistance

  a 6K wick (6,000 fiber-s) of carbon fiber in which each fiber has a

7 to 20-miorons.

  The term "foam", "foam body" or "Foam structure" as used herein covers products such as particles, sheets, coatings and the like.

  plates or other shaped products.

  All percentages shown here are in

percent by weight.

  The subject of the present invention is a flame retardant composite product structure comprising a polymeric foam and a. at least 0. 5% of linear and / or non-linear carbonaceous fibers which are substantially irreversibly and non-flammable and which are disposed on at least one of the surfaces of the foam

  and / or distributed within this foam, the

  so-called carbonaceous fibers having an oxygen limit index (ILO) value greater than 40 and the fibers

  Linear markers with electrical resistance

  greater than or equal to 4 x O103 -ohms / am when measured on a 6 K fiber wick,

  each fiber having a diameter of 7 to 20 microns.

  The invention also relates to a process for manufacturing a flame retardant composite product comprising a polymer foam, characterized in that it consists in reacting, in situ, a reaction mixture generating polymer foam and introducing it into this mixture reaction of 0.5 to 30% of stabilized linear and / or non-linear carbonaceous fibers

  in a substantially irreversible and inno-

  flammable, these fibers having an oxygen limit index (ILO) value greater than 40 and a dimensional ratio greater than 10: 1, the linear carbonaceous fibers having an electrical resistance greater than or equal to 4 x 103 ohms / cm when it is measured on a wick 6 K of fibers, each fiber

  having a diameter of 7 to 20 microns.

  The invention also relates to a composite panel structure, comprising a rigid polymeric foam panel comprising at least 0.5% of linear and / or nonlinear carbonaceous fibers, stabilized, heat-fixed in a substantially irreversible and non-flammable manner. possessing

  an ILO value greater than 40 and a

  greater than 10: 1, distributed over at least one of the panel surfaces. Another object of the invention is a composite panel structure comprising a rigid foam board containing up to 30% of linear and / or non-linear carbonaceous fibers. stabilized, heat-sealed in a substantially irreversible and non-flammable manner, possessing

  an ILO value greater than 40 and a

  sicnne] superior '10: 1, distributed throughout the mass of the panel. The invention relates, more particularly to a foam cushion, comprising a flexible foam containing at least 0.5% of linear and / or non-linear carbonaceous fibers, stabilized, substantially irreversibly heated and non-flammable, having a higher ILO value. and a dimensional ratio greater than 10 1, distributed over at least one of the faces of the cushion. Another foam cushion, according to the invention, comprises a flexible foam containing up to 50% of linear and / or non-linear carbon fibers. linear, stabilized, substantially irreversibly heat-resisting and non-flammable, having an ILO value greater than 40 and an aspect ratio greater than 10 2 i,

  distributed throughout the mass of the cushion.

  The present invention also aims, in particular

  Culier, the use of polyurethane foams in aircraft. Fires in aircraft are difficult to extinguish when decaying, since adequate fire-fighting equipment is not readily available because of weight and space limitations, lack of storage capacity in the aircraft and the

  knows that it is impossible to evolve around

  gers. It is therefore a preferred object of the invention to provide a polyurethane foam for use as a. seat cushion, which is flame retardant, does not melt or break without

  flame and which is self-extinguishing.

  The invention also relates to the use of fire-resistant structures, more particularly in aircraft, comprising a layer of polymer foam,

  such as neoprene, and a similar layer of flakes

  wool or a topping consisting of a very large ID number of carbon fibers arranged on at least

  one of the surfaces of the polymer foam.-

  The carbonaceous fibers used in the invention have an ILO value greater than. 40, when determined by the ASTM D 2663-77 test method. This test method is also known as the "oxygen index" f or "oxygen limit index" (IL0). According to this test, the oxygen concentration for which a sample placed vertically, to which it has been placed, is determined in 02 / NZ mixtures. the fire at its upper end, just continues to burn. The sample size is

  0.65 x 0.3 cm with a length ranging from 7 to 15 cm.

  The ILO value is calculated from the equation: ILO = {-72: + N223x 100 Advantageously, the carbon fibers are constituted by linear and / or non-linear fibers; ininîlammables. having a diameter of 7 to 20 microns and a dimensional ratio (1Z / dj greater than 10: 1). The nonlinear carbene fibers are elastic, reshape and have a reversible deformation ratio of greater than 1.2: 1. a 2: 1. Both linear and non-linear carbon fibers have an ILO value greater than 40 and, in combination with a polymer foam, provide this synergy effect with respect to the flame retardant and self-extinguishing characteristics of the foam. Generally speaking, a relatively small proportion of carbonaceous fibers, for example less than 0.5 percent, can be used, based on the total weight of the fiber-foam composite product.

  carDonées, 'where the tibers are intended primarily

  Payment has to be arranged on the outside surface of the sea. It will be understood, of course, that a greater proportion of the carbonaceous fibers may be used when it is desired to achieve a cut-off structure. Such a structure can be presented under the term of a panel comprising a sheet of foam

  polymer having a layer, for example a nap-

  page, felt, mat, scrim, woven fabric or the like, formed by the carbon fibers and disposed on at least one of the surfaces of the foam such that the proportion of fibers reaches 90%. In the composite structure, the carbonaceous fibers and the polymer foam act in combination to retard the propagation of the flames and to quench any smoldering fires that may be present on the surface of the object or structure. In order to impart to the composite structure flame retardant and self-extinguishing characteristics throughout its mass, the proportion of the carbonaceous fibers should be increased and these fibers should be distributed throughout the mass of the foam. In general, in it is preferable to use from 5 to 30% of non-linear caroOne fibers. It is possible to cut this base product into plates of suitable sizes and shapes, so as to ensure the required flame retardancy. throughout the mass of the foam structure. When using only linear carbon fibers, it is preferable to use 9.

use with less than 10 s.

  - It has been surprisingly discovered that

  when carbonaceous fibers, especially

  nonlinear ribres, has a foam generating reaction mixture, a substantial portion of the fibers

  will be distributed on the surface-

  outer of the foam structure thus formed if the reaction mixture is not agitated. Even more

  surprising is the fact that the distribution is

  uniformly on the outer surface of the foam structure. Proportions of 0.5 to 10% of carbonaceous fibers have been found to be sufficient to obtain a reliable distribution of the carDonated fibers, forming a flame retardant and protective screen on the

  outer surface of the foam structure.

  The necessary proportion of carbonaceous fibers will depend on the degree of flame retardancy desired for the foam. However, the proportion of carbon tibers, when distributed throughout the mass of the foam, will usually not exceed about 30%, so as to retain the physical characteristics

  initials of a notable part of this foam.

  The carbonaceous fibers may be the only flame retardant additive present in the foam generating reaction mixture. Moreover, in addition to these carbon fibers, it is possible to use other

  igniter additives known per se, such as, for example,

  compounds containing halogen and / or phosphorus

  phore, antimony oxides, compounds containing

boron and similar compounds.

  The carbonaceous fibers which may be used in the invention come, preferably, from carbon fibers, stabilized with oxygen and fixed to heat in a substantially permanent or irreversible manner, having a nitrogen content of up to 30%. . These fibers are classified in three groups according to the particular use and environment where the structures are put in place.

  in which they are incorporated.

  In a first group, the non-flammable carbon fibers are non-electrically conductive and have no electrostatic dissipation characteristics. The term "non-conductive of electricity" as used in the present application relates to: carbon fibers having a carbon content of greater than 65% but less than 85% and an electrical resistance of more than 4 x 10 6 ohm / cm when measured on a 6.K (6,000 fiber) fiber tow. each fiber having a diameter of 7 to 20 microns The specific resistivity of the carbon fibers is greater than about 10 ohms.cm. This specific resistivity of the fibers is calculated from measurements made in the manner described in the published European patent application.

No. 0199567 mentioned above.

  When the precursor fiber is a stabilized and hot-set acrylic fiber, it has been found that a nitrogen content of 18% or more gives one. fiber

non-conductive electricity.

  In a second group, the fibers

  are classified as being partly

  These fibers have a carbon content of greater than 60% but less than 85%. The percent nitrogen content of such fibers is, in general, 16 to 20%. In fibers derived from an acrylic terpolymer, the nitrogen content may be higher. Low conductivity means that a 6 K fiber core in which the fibers individually have a diameter of 7 to -20 microns has a resistance of 4 x 10 6 to 4 x 10 3 ohm / cm. Such fibers can be used to dissipate the electrostatic electricity accumulated in

the composite foam structure.

  A third group is oarbonyl fibers having a carbon content of at least 85% and a nitrogen content of less than 16%. Because of their high carbon content, these fibers have good electrical conductivity. This means that the fibers are substantially graphitic and have an electrical resistance of less than 4 x 13 ohm / cm and a nitrogen content of less than 5%. On the one

  corresponding way, the electrical resistivity of.

  these fibers are less than 1 OD / ohms.cm.

  The precursor acrylic filaments which are preferably used to prepare the cardboard fibers are chosen from acrylonitrile homopolymers, acrylophile copolymers and

terpolymers of acrylonitrile.

  The acrylic copolymers and terpolymbers preferably contain at least about. 85 mole percent acrylic units, preferably acrylonitrile units, and up to 15 mole percent urea or more copolymeric monovinyl units with styrene, methacrylate acrylate, methyl methacrylate, viny.e chloride. vynylidene chloride, vinylpyridine

and these analogous compounds.

  It will further be understood that the carbon precursor starting material can be imparted with a property of conduction of electricity which is of the order of magnitude of that of the metallic conductors by heating the material of the carbon fiber, which can in the form of a wick of fibers, yarn, surface-like flakes, toppings or the like, up to a temperature of above 1000 ° C. This property of conducting electricity can be obtained from selected precursor starting materials such as materials. base of tar (petroleum or coal), polyacetylene or acrylonitrile, for example polyacrylonitrile -FANOX narque deposited R.K.Texti-them) or- GRAFIL-Ol (registered trademark),

  polyphenylene and related compounds.

  Preferred precursor materials are prepared by making a known yarn, the melt spinning or the wet spinning of the materials.

  precursors, to give a wick of monofilament fibers

  mente (generally having a diameter of 4 to 25

  micron) or a multifilament fiber worm.

  firing of its fibers, son or meshes, we then make a

  knitted yarn or fabric weaves using one of the

  available commercially. The fabric or fabric obtained, preferably at a temperature above 550 ° C., is then heated in order to fix them.

  fibers to heat in a substantially

  manent or irreversible. The term "permanently or irreversibly attached to heat" as used herein refers to carbonaceous fibers constituting a precursor material, which have been heat-treated while in a non-linear form, for example in the form of a helix or in sinusoidal form, and under tension, until they have a degree of irreversibility such as

  linear, when stretched to a sensitive shape

  If linearly, Without exceeding their internal tensile strength, substantially return to their nonlinear contiguration kings that remove the stress applied to the fiber. The fabric or canvas is then subjected to. unraveling and an opening operation to produce flooons similar to

  wool which can then be put into an analogous form

to a topping.

  Carbon fibers, when they are not

262658 1

  found on the outer surface of the foam body, are preferably non-linear ie

  sinusoidal and / or helical, or

  nonlinear guration more complex. Advantageously, proportions up to about 10% of these non-linear fibers are used to produce a composite structure in which the fibers are mainly located on or near the outer surface of the foam body. this. According to one embodiment of the invention, the reaction mixture is reacted to produce the foam while enclosed in

  a container or a reaction vessel without stirring.

  When the fibers have a non-linear configuration, these fibers move during the reaction under the effect of the expanding mixture in such a way that they focus on the surface of the reaction.

  the foam or just below this surface.

  In an exemplary embodiment, the foam generating reagents are reacted in a

  mold, the fibers being in the form of fo-

  This is because the wool is placed in this mold before the foam generating reaction mixture is introduced into it. It will be understood that it is also possible to coat the interior of the mold with a layer formed of a carbon fiber structure in the form of a ply, felt, non-woven mat or a similar product, or a woven or knitted fabric or fabric. In such a case, it is possible to use linear and / or non-linear carbon fibers.

l inesires.

  In another embodiment of

  the invention, a composite foam structure has been prepared

  posite having an effective proportion of corona fibers distributed throughout the mass of the foam (przauit base plates) to ensure igniting and self-extinguishing properties throughout the mass of the foam plate, in such a case, prepares the composite structure by mixing the filtrates and the foam-generating reaction mixture S-all, triggering the foam-generating reaction, The carbonaceous fibers can be present in a proportion of up to about 30% without breaking in a measure practice features

-physical initials of the foam.

  From the past, the polymer modsse that or. In the invention, it is possible to use a polystyrene foam, a polyolefin foam, a urea foam, a latex foam, a polyurethane foam and an isocyanurate foam. Epoxy resins can also be used as binder

for carbon fibers.

  The composition of the polychre sprout can

  be formulated in such a way that it is of a nature.

  pie, semi-rigid or rigid. The foam structure

  composite of the invention may be in the form of

  titles, coverings, upholstery, panels; trim

  or cushion for seats, boxes, structural objects

  turmoil of complex tormes, such as can be

  to mold in a mold, or produced analogues.

  The polyurethane foams used in the present invention are preferably prepared from

  of a polyhydric alcohol which is reacted by mixing it.

  with aqueous polyisodanurate. The foam thus produced

  duite caraotéPise by a molecular network

reticle.

  The polyalcohols used in the preparation of the foaming polyurethane according to the present invention preferably have an average molecular weight of 200 to 20,000, more preferably 600 to 6.GOD, with a hydroxyl functionality of 2 or more preferably 2%. In a conventional manner, the polyhydric alcohol is reacted with a polyisocyanate in the presence of the carbonaceous free radicals. The reaction can be carried out in an inert atmosphere, for example under a nitrogen layer, at atmospheric pressure and at room temperature. a temperature of between 0 ° C. and 120 ° C., over a period of time up to 20 hours, depending on the temperature and the intensity with which it is agitated. the reactional mixture. We can

  also carry out the reaction under the ambi-

  antes. The reaction is carried out using stoichiometric proportions of reagents. However, it is in some cases desirable to use an excess of polyisocyanate to provide a reaction.

  complete polyalcohol. The report of the radicals iso-

  cyanate with hydroxyl radicals is generally understood

  between 1 and 4 isocyanate radicals per hydroxyl radical.

  As the palyisocyanates used in the reaction, a polyeryl polymethyl polyisocyanate, as described in US Pat. No. 2,663,73U, for example 1,3-triisocyanate-1,3 benzene, chlorophenyl diisocyanate, 2,4-triisocyanate, may be used. 4 'of diphenyl, 4,4'-diisocyanate of diphenylmethane,

  3,3'-dimethoxybiphenylene-4,4'-diisocyanate and similar compounds

guages.

  Aromatic diisocyanates and cycloaliphatic diisocyanates and polyisocyanates or mixtures thereof,

  having a high degree of activity, which are easily available

  suitable for use in the reaction.

  The polystyrene foams used in the invention can be prepared by conventional methods. The techniques

  currently known for the preparation of expanded polystyrene consist in the extrusion of a thermoplastic resin gel mixed with an agent

  volatile blowing agent in a low pressure zone o this volatile blowing agent vaporizes and forms multiple gas cells inside the extruded gel. This gel is then cooled

  extruded cell to form a self-supporting cellular foam body

  carrier. A wide variety of blowing agents are known which

  mainly fall into the class of aliphatic hydrocarbons

  such as butane, hexane, heptane, pentanes and the like, as well as gases (which are suitable in a pressurized polymer) such as carbon dioxide. In an advantageous manner, certain fluorinated hydrocarbons such as

  trichlorofluoromethane, trifluoromethane and similar compounds

  as well as chlorohydrocarbons such as

  methyl. Many of these swelling agents prove to be satisfactory.

  with various polymeric materials.

  The following examples illustrate the invention.

Example 1

  A flexible polyurethane foam was prepared by mixing in a cup of the size of 1 liter. parts by weight (pep) of a polyether-triol having an average molecular weight of about 3,000 (available commercially from The Dow Chemicael Compahy under the trade name VORANOL 3137), 4.3 phr of water, 1 2 pep of L-540 (commercially available silicone surfactant from Union Carbide Corp.) and Dabco 33 LV (33 percent mixture of triethylenediamine in dipropylene glycol, commercially available from Air Products Co.). We pay

  mixture in a 2-liter cup containing 1 μl of carboard fibers

  sinusoúdales bonuses. The reaction was started by adding a separate mixture of 1.715 phr of stannous octoate catalyst and 45.2 ml of an 80/20 mixture of 2,4-diisocyanates and -2,6 toluene. Stirring was stopped when the reaction started. The resulting mixture has foamed

  and filled the dish with a soft foam o the car-

  bonées are incorporated in the outer layer of the expanded foam.

Example 2

  The procedure of Example 1 was repeated with the only difference that 10 pep of linear carbonaceous fibers were used in place of the sinusoidal fibers. Moreover, the reaction mixture was mixed continuously when the

reaction has begun.

0 17

  The foam obtained had carbon fibers of 0.2 to 0.4 mm distributed throughout its mass. This foam has constituted stable products with excellent value of insulation and density

relatively small.

  In the following examples, several foams were prepared under varying conditions, each using the sampling mode described above. In each case, a polymer was heat-plastified in an extruder,

  substantially as disclosed in U.S. Patent 2,669,751.

  and a volatile fluid swelling agent was injected into the hot plasticized polymer stream. From the extruder, the plasticized gel was heated in a mixer, this mixer being a rotary mixer in which a spiked rotor is enclosed in a housing which has a spiked inner surface which intersects with the rotor tips. The heat-plastified gel from the extruder is introduced into one end of the mixer and extracted at the other end, the flow being in a direction in the axial assembly. From this mixer, the gel passes into cooling apparatus, such as those described in U.S. Patent Nu2. 669.751, and from these devices to a die which extrudes a substantially rectangular plate. After extrusion, a foam having a density of one cell size, a compressive strength, a permeability to the

  water vapor and thermal conductivity which are suitable.

Example 3

  A polystyrene having a viscosity of 14 is introduced.

  Centipedes (measured as a 10% solution in toluene) in an extruder, at a rate of 541 parts per wt. per hour together with a mixture of nelice or sinusoidal carbon fibers having nitrogen content of about 18, M1, so as to constitute 2U% of the foam obtained. The blowing agent consists of a 1: 1 mixture by weight of methyl chloride and dichlorodifluoromethane which is injected into the plasticized polymer while hot before it enters the mixer. One uses a feed 18 '.

  total. of ZO, 3 x 10-4 moles of blowing agent per gram of poly-

  styrene. As a nuc1lation agent,

  0.06 part -indigo for 100 '. parts of polystyrene.

  A stable rectangular plate having a cross-sectional area of 5.6 cm x 6 cm cm is extruded at a temperature of 121 ° C. The fibers are distributed substantially uniformly throughout the mass of the foam. The foam obtained has

antistatic characteristics.

Example 4

  -10 we have. two flammability tests on a foam mixed with carbon fibers. Test A was the Test

  of Flammability at 45 * (AATCC test method 33-19X2 - Inflamma-

  It is the same as that described in Title 16 of the Commercial Practices, Part 1610, of the Code of Federal Regulations (U.S.). This test consists of projecting a flame of 16 mm (butane) for one second on a sample of 5 cm x 15 μm maintained at an angle of 45. The samples of the invention failed to ignite, even when the

  projection of the flame for a period of 90 seconds.

  The second test, Trial B, was the 9U0 angle test used to test children's sleepwear (see U. S. Department of Commerce Standard DOC FF 3071 (tel.

  as amended) and FF5-74). This method consists of exposing an

  - 5 cm x 25 cm, suspended in a vertical position, at a Bunsen burner .- (propane gas or methane) so that 19 mm from the lower edge of the sample is in the flame for 3 to 12 seconds. The samples of the invention failed to

  ignite even after a period of 10 minutes in the flame.

  This test is considered to be the most common test method

  severe and is mainly used to test inactive fibers.

  flammable or flame retardant. The results are presented in the following table X

(see page 21) -

  The above samples were successfully submitted, which means that none could be ignited or burned in

the test conditions used.

Example 5

  Noninflammability of the composite foam structures of the invention was determined by following the test procedure set out in 14 CFR 25.853 (b). This test was carried out as follows:

  A minimum of three samples consisting of

  foam / carbon fiber site, containing 3UA of carbon fiber, 2.5 cm x cm x 3 cm, keeping these samples in a conditioning room maintained at a relative humidity of 70 ° C during the 24 hours preceding the test . The foam was polyurethane. We suspended. each sample vertically and presented to a Bunsen burner having a nominal inside diameter tube of 3 .mu.m in height. The minimum flame temperature measured using a calibrated thermocouple pyrometer in the center of this flame was 843 ° C. The lower edge of the sample was 1.9 cm above the upper edge of the burner. The flame was applied for 12 seconds on the assembly line of the lower edges of the samples, then

* removed it.

  Following the test, the morning of the invention was considered to be self-extinguishing. The average length consumed did not exceed 20 cm, the moryen persistence of the flame did not exceed 15 seconds and there was no

fall of inflamed drops.

  The same results can be obtained with urea, polystyrene, polyolefin and isocyanurate foam structures.

latex or epoxy resin.

Example 6

  Following the procedure of U.S. Patent 4,640,933, -

  a composite structure based on polyurethane foam has been prepared.

  olefin possessing flame retardant characteristics, by mixing in the reaction mixture, before swelling, 20% of sinusoidal carbon fibers having a carbon content of about 10%. This sample also failed to ignite or burn under the test conditions used above. Processing temperature, Thickness of fiber to the coating fiber Sample Carbon test (C)% Foam type Foam in mm 1 A 7? 550 30 Celluletic Acrylic Finisher Latex 6.25 2 * - 2U 65U 80 Cured Cellular Acrylic Latex 6.25 3 to 50 650 50 Crosslinked Epoxy DER 3.2U * Sample 2 was tested by projecting an air / acetylene flame (flame temperature 2460 "C) on the face of the sample for 30 seconds The sample failed to ignite or burn and the surface opposite the tip of the projected flame remained cold enough to can touch it with an unprotected finger. Co Qs. co

DREAM: NDICATIONS

  A flame retardant composite product structure comprising a polymeric foam and at least 0.5% linear carbonaceous fibers

  and / or non-linear, hot-fixed in a substantially irreversible manner.

  pourable and noninflammablepossibleto at least one of the surfaces of the foam and / or distributed within said foam, said carbonaceous fibers having an oxygen limit index (ILO) value greater than 40 and the fibers linear carbonaceous materials having an electrical resistance greater than or equal to 4 x 10 ohms / cm when measured on a 6 K wick

  fibers, each fiber having a diameter of 7 to 20 microns.

  2. Composite structure according to claim iy carac-

  characterized in that the carbonaceous fibers have a diameter of 7 to 20 microns and one. dimensional ratio (l / d) greater than 10: 1, -15 3. Composite structure according to one of the

  Claims 1 or 2, characterized in that the carbonaceous fibers

  nonlinear have a sinusoidal and / or helical configuration and a higher reversible deformation ratio

b 1,, Z: i.

  4. Composite structure. following one of

  Claims 1 to 3, characterized in that the carbonaceous fibers

  come from stabilized polymeric precursor fibers or tar-based precursor fibers with a

upper carbon b 65X.

  5. Composite structure according to claim 4, characterized

  characterized in that the polymeric precursor fibers are acrylic fibers selected from acrylonitrile homopolymbils, acrylonitrile copolymers and terpolymers of a-acrylonitrile, these copolymers and terpolyneres containing at least 85 mole percent acrylic units and up to to 15 mole percent of one or more monovinyl units copolymerized with another polymber. 6. Composite structure according to one of the

  Claims 1 to 5, characterized in that the carbonaceous fibers

26.26581

  have a carbon content of at least 85%, are

  conductors of electricity, have a lower electrical resistance

  than about 4 x 10ohms / cm and a specific resistivity

than about 10 ohm.cm.

  7. Composite structure according to one of the

  Claims 1 to 5, characterized in that the carbonaceous fibers

  have a carbon content of less than 85%, are non-conductive

  of electricity or have no characteristic of dissipation of electrostatic electricity, and have a resistance

  greater than 4 x 10 ohms / cm and a resistivity -specific-

  than greater than about 10- ohms.cm.

  8. Composite structure - following one of the

  Claims 1 to 5, characterized in that the carbonaceous fibers

  have a carbon content of less than 85%, have a

  low electrical conductivity and dissipative characteristics

  electrostatic electricity and have an electrical resistance

  4 x 106 to 4 x 10 ohm / cm.

  9. Composite structure according to one of the

  Claims 1 to 8, characterized in that the foam is a

  rigid, semi-rigid or flexible polymer material.

  Composite structure according to one of the

  Claims 1 to 9, characterized in that the polymeric foam is

  selected from polyurethane, urea, latex,

  polyolefin, polystyrene or isocyanurate.

  It, composite structure following one of the

  claims 1 to 1U, characterized in that at least 0, 5% of

  carbon fibers are spread over substantially the entire surface

outer foam.

  12. Composite structure according to one of the

  Claims 1 to 10, characterized in that at least 10% of fibers

  linear carbonaceous are distributed throughout the mass of the foam. 13. Composite structure according to one of

  Claims 1 to 11, characterized in that the foam contains

0.5 to 30 carbon fibers.

  A method of manufacturing a flame retardant composite product comprising a polymeric foam, characterized in that it comprises reacting, in situ, a polymer foam generating reaction mixture and introducing into said reaction mixture a reaction mixture of 0. 5 to 30 U of linear and / or non-linear carbonaceous fibers, stabilized, substantially irreversibly heat-stable and non-flammable, these fibers having an oxygen limit value greater than and a dimesional ratio greater than 10 1 linear carbonaceous fibers having an electrical resistance greater than or equal to 4 x 103 ohms / cm when measured on a 6 K fiber wick, each fiber having a diameter of 7 to

microns.

  15. The method of claim 14, characterized in that the fibers are non-linear and at least 0.5% of carbon fibers are distributed over at least one

outer surfaces of the foam.

  16, Process according to one of the claims

  14 or 15 is characterized in that at least 10% of carbonaceous fibers

  linear are distributed throughout the mass of the foam.

  17. Process according to the claims

  14 to 16, characterized in that the foam contains from 0.5 to 3% of

carbon fibers.

  18. Composite panel structure, characterized in that it comprises a rigid polymeric foam panel comprising at least 0.5% of linear and / or non-linear carbonaceous fibers,

  heat stabilized in a substantially irreversible manner.

  sible and non-flammable, with an ILO value greater than 40 and a dimensional ratio greater than 10: 1, spread over

  at least one of the panel surfaces.

  19. Composite panel structure according to claim

  cation 18, characterized in that the carbonaceous fibers are

  tent in the form of. wool-like flakes, toppings, felt, mat,

  canvas, or woven or non-woven fabric.

  20. Composite panel structure, characterized in that

-.

  it comprises a rigid foam board comprising up to 3% of linear and / or non-linear carbon fibers stabilized,

  attached to heat in a substantially irreversible and inIn-

  flammable, having an ILO value greater than 4U and a dimensional ratio greater than IU: 1, distributed throughout the mass of the panel. Foam cushion, characterized in that it comprises a flexible foam comprising at least 0.5 t of linear and / or nonlinear carbonaceous fibers stabilized substantially irreversibly hot and nonflammable, having an IL value greater than 40 and a dimensional ratio greater than 1: 1, distributed over the extent of at least one of the surfaces of the cushion.

  Foam cushion according to Claim 21, characterized in that

  in that the carbonaceous fibers are in the form of wool-like flakes, toppings, felts, mats, scrims or woven or non-woven fabrics.

  Foam cushion according to claim 21 or 22, characterized

  characterized in that it comprises a flexible foam comprising up to% stabilized linear and / or non-linear carbonaceous fibers,

  heat-set in a substantially irreversible and ininflammatory

  with an ILO value greater than 40 and a

  greater than 10 1, distributed throughout the mass of the cushion.